The invention relates to a foot lock ascender for ascending along a rope, comprising:                an ascender element having a metal body equipped with a throat for guiding the rope, and a movable gate mounted pivoting on the body around a swivel-pin between a closed position and an open position to respectively press the rope against the bottom of the throat when the body is solicited in the descending direction and to release the rope in the opposite ascending direction,        a first attachment device comprising at least one passage for a first strap designed to wrap round the user's ankle to pass through, and a second attachment device of a second strap designed to pass under the sole of the user's shoe.        
Such an ascender can be fixed to the shoe of the right or left foot and makes for easier ascending along a rope in the field of mountaineering, rock-climbing, caving, or working at heights.
The first strap surrounds the instep and is associated with a securing loop, whereas the second strap passes under the shoe and is secured to the first strap opposite the second strap passage.